Porsche 918 RSR hybrid
16th January, 2011
Porsche has fused together its 918 concept car of 2010 with
an even higher-performance hybrid drive from last year’s 911 GT3 R Hybrid to make the new Porsche 918 RSR.
Porsche’s new car at the Detroit Motor Show is the latest “race lab” for Porsche – showcasing what
happens when the technology fitted in the 911 GT3 R Hybrid unites with the smooth exterior of the 918
Spyder, but this time in a coupe body style.
The two-seater, mid-engined 918 RSR coupe is an innovative ‘sports car‘ – a true motor sports version
of the 918 Spyder concept. Motor racing technology also dominates within the particularly light,
torsionally stiff carbon fibre-reinforced plastic (CFRP) monocoque.
The 918 RSR takes the technology and learnings from real-life racing of the 911 GT3 R Hybrid at the
Nürburgring Nordschleife circuit, American Le Mans Series races (ALMS) in Road Atlanta, and the ILMC run
in China's Zhuhai to an even more powerful and intelligent level.
The Porsche 918 RSR uses a highly-efficient flywheel accumulator to store power from its own dynamics
when braking. This power is then fed to the front axle where an electric motor at each wheel provides an
extra 75 kW of driving power for a total of 150 kW.
This 150 kW is in addition to the 420 kW provided by the direct-injection V8 engine – a further
development of the successful RS Spyder race car engine – which drives the rear wheels and delivers peak
power at 10,300 rpm. Overall power is therefore an impressive 570 kW.
In the 918 RSR, the two electric motors for the front wheels offer a torque vectoring function with
variable torque distribution. This additionally increases agility and improves steering response. Mounted
forward of the rear axle, the mid-engine is integrated with a racing transmission also based on the RS
Spyder race car. This further developed six-speed constant-mesh transmission with longitudinally mounted
shafts and straight-toothed spur gears is operated using two shift paddles behind the racing steering
The flywheel accumulator is an electric motor whose rotor rotates at up to 36,000 rpm to store
rotation energy. Charging occurs when the two electric motors on the front axle reverse their function
during braking processes and operate as generators. At the push of a button, the driver is able to call
up the energy stored in the charged flywheel accumulator and use it during acceleration or overtaking.
This additional power is available for around eight seconds when the system is fully charged. In the
911 GT3 R Hybrid this additional power is also used as a consumption aid depending on the racing
situation, e.g. to delay pit stops or reduce the fuel tank volume and therefore the car’s weight.
From the tradition established by classic Porsche long-distance race cars such as the 908 long-tail
coupe (1969) and 917 short-tail coupe (1971), Porsche designers have with the 918 RSR made a modern
interpretation of the ‘form follows function‘ philosophy. The 918 RSR’s exterior is dominated by
'muscular' wheel arches with air intakes, a visible fan wheel through the centre of the engine cover
and a large rear spoiler of RS Spyder dimensions. The new ’liquid metal chrome blue‘ colour highlights
the body’s curves while the typical Porsche hybrid orange colour on the brake callipers and body stripes
add a further touch.
There is no mistaking the 918 RSR’s race track intent. Whether it be the characteristic wing doors
which open upwards, the air intake in the roof between the doors, the quick-action locks on the front and
rear CFRP lids, the two roof mounted aerials for pit radio and telemetry, the RS Spyder-like small,
lateral front winglets, the air splitters beneath the front lip or low-profile racing slicks on
centre-locking 19" wheels.
In contrast to the 918 Spyder concept car, the coupe’s interior is clean and minimalistic. The
figure-hugging bucket seat's brown leather hark back to the history of the gentleman driver while the gear
flashes on the racing steering wheel and a recuperation display on the steering column in front of the
display screen supply the driver with vital information.
Instead of the futuristic, ergonomically avantgarde centre console with touch sensitive user interface
from the 918 Spyder concept car, the 918 RSR's cockpit is split by a simple console with rocker switches.
And instead of a second seat, the flywheel accumulator is positioned to the right of the console.
Finally, the starting number, 22, pays homage to a remarkable motor sport triumph. Drivers Dr. Helmut
Marko and Gijs van Lennep were the first to cross the finish line in 1971's 24-hour classic. The distance
record set by their Porsche 917 short-tail coupé – 5,335.313 kilometres at an average speed of 222.304
km/h – remained unbeaten for 39 years. At the time, the 917 was also a “race lab” for Porsche with its
experimental magnesium space frame setting new standards in lightweight construction.
With the new 918 RSR “race lab” Porsche is now elevating this motor racing hybrid concept to a higher
level where sustainable efficiency can be proven under intensive racing conditions before lessons learned
can be transferred to regular production cars.